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← Fossil microbes give sulphur insight on ancient Earth

Fossil microbes give sulphur insight on ancient Earth - Comments

Alan4discussion's Avatar Comment 1 by Alan4discussion

At last we have good solid evidence for life over 3.4 billion years ago.

It is good to have evidence of life this early in Earth's history, but it is hardly news that there was life before an oxygen atmosphere, given that later life created the oxygen atmosphere.

But more than that, the fossils are associated with tiny crystals of "fool's gold" - the pyrite mineral composed of iron and sulphur.

The types of atoms, or isotopes, present in these crystals point to the pyrite being formed as a by-product of cellular metabolism based on compounds of sulphur.

There would have been lots of iron dissolved in the water at this stage, but once oxygen generation by other life got under way, this iron would turn to insoluble rust and be precipitated as the iron ore deposits we have today.

Thu, 25 Aug 2011 21:33:52 UTC | #864268